This proposal integrates engineering sciences with the life sciences in order to advance scientific understanding of the pathogenesis, risk factors, and potential methods for treatment and prevention of joint injury and degenerative joint disease, with the goal of enhancing medical care of these diseases. Musculoskeletal diseases, of which osteoarthritis (OA) is the most common, are one of the leading causes of disability in the United States. The importance of these diseases is illustrated by the fact that the decade 2002-2011 has been declared the Bone and Joint Decade. They affect men and women, old and young, humans and domestic animal species. There are many risk factors, some of which cannot be controlled such as genetics, gender, and age, but others can be manipulated such as muscle weakness and joint conformation. Horses, like humans, are athletes and are subject to similar joint injuries and diseases such as subchondral bone necrosis, fracture, and OA. Therefore, this proposal uses the horse as a model for human disease. The specific aims of this proposal are focused into 3 areas: 1) The development of a computer model of the equine metacarpophalangeal joint using the finite element (FE) method;2) The correlation of specific joint parameters such as contact area to measures of bone quality;3) The application of the FE model to study the role of joint geometry in osteochondral disease. By developing and validating a computer model, various factors can be controlled and investigated separately and in conjunction to determine their possible relevance and contribution to joint injury and degeneration and thus focus clinical research on the most promising factors related to the initiation and progression of osteochondral disease. This same model can then be used to examine methods of treatment and prevention. For example, it can be used to investigate how orthotics or surgery can alter biomechanical loading within a joint in order to minimize areas of stress concentrations that can lead to abnormal bone modeling or how muscle strengthening can stabilize a lax joint. While the actual techniques and computer model will be developed using a horse, the information gained will benefit not only the horse, but humans as well by increasing the overall understanding of osteochondral disease. The horse as a research animal can allow for invasive testing for validation of the model. In addition, this research will set the framework for using similar techniques in human medicine. PUBLIC HEALTH RELEVANCE: This proposal will enhance the understanding of the processes and risk factors underlying degenerative joint diseases such as osteoarthritis. With a greater understanding of these diseases, advancements in their treatment and prevention can be made.